1. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Mariana Petris, NIPNE - Bucharest C B M In-Beam Test Results of the Pestov Glass Resistive Plate Counter Prototypes

2. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Motivation Standard Read-out Pestov Glass RPC Prototype - Construction Details - 60 Co Source Test - In-Beam tests Differential Read-out Pestov Glass RPC Prototype - Construction Details - In-Beam tests Conclusions and Outlook Outline

3. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna RPC Counting Rate Performance MSMGRPC based on commercial float glass (  glass ~ 10 12  cm) keeps the performances up to ~1 kHz/cm 2 ; this type of RPC could be a solution for a major part of the CBM - TOF subdetector. CBM - TOF subdetector at small polar angles – high counting rate environment (up to 20 kHz/cm 2 ). Solutions: –Electrodes with lower resistivity –Smaller and many gaps Our prototypes were built using Pestov glass with  ~10 10  cm.

4. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna 1 2 3 glass sampl e Volume Resistivity Measurements of Pestov Glass Experimental Setup Measurement Setup: Device – Keithly Picoampermeter 487; Measurement Duration – 100 ps; Applied voltage – 100 V; Condition – 22 0 C, 42 % LF Power supply pA-Meter Measurement electrode Measurement electrode Guard-ring Conductive rubber sample Counter electrode Point 1Point 2Point 3Point 4

5. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Electrode sequence: - 2 mm aluminum – cathode - 0.3 mm nylon fishing line - 2 mm glass plate (supporting the spacers) - 0.3 mm nylon fishing line - 2 mm glass plate - 0.5 mm double faced strip readout plate symmetry plane Readout electrode: - support:0.5mm thick pcb plate - 14 copper coated strips on each side - pitch: 2.54 mm, 1.10 mm strip width, 1.44 mm gap width Sizes: glass electrodes: 40.6 x 300 mm 2 readout plate: 0.5 x 40.6 x 360 mm 3 housing: 40 x 80 x 330 mm 3 Al box Construction details of the standard – readout Pestov glass RPC prototype

6. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna 60 Co Source Test 85% C 2 F 4 H 2 +10% SF 6 + 5% izo-C 4 H 10  ≤ 60 ps

7. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna In-Beam Tests @ ELBE (Electron Linac with high Brilliance and low Emittance) Forschungszentrum Dresden-Rossendorf Experimental setup: - electron beam, 30 MeV, scattered @ 45 0 by a 18  m Al foil; - plastic scintillators S5(XP2972), S12(XP2020), S34(XP2020), (2 x 2 cm 2 ) used for active collimation; - signal amplification: FEE1 developed for FOPI at GSI. - digital converters: CAEN ADC V965, CAEN TDC V1290N - DAQ – MBS (Multi-Branch System – GSI – Darmstadt) - information recorded for 4 central strips V. Ammosov et al., Nucl. Instr. And Meth. A 576 (2007), 331

8. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Time resolution

9. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Time resolutions of the strips 6 and 7 Strip no. 6 Strip no. 7 Cond. Qmax

10. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Time resolution of the strips 8 and 9 Strip no. 8Strip no. 9 Cond. Qmax

11. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Position dependence Strip no. 8 No significant position dependence for strip # 6,7,9.

12. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Time resolutions of the 4 measured strips These results have been obtained No correction for the intrinsic electronic time resolution These results have been obtained with a uniform exposure of the counter active area at a particle flux density of ~1kHz/cm2.

13. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Rate dependence No saturation effect of the number of events recorded by the Pestov glass RPC as a function of counting rate

14. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Differential Strip – Readout Pestov Glass RPC Prototype

15. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna In-Beam Tests @ ELBE (Electron Linac with high Brilliance and low Emittance) Forschungszentrum Dresden-Rossendorf Experimental set-up: - electron beam, 28 MeV, scattered @ 45 0 by a 18 μm Al foil; - plastic scintillators S5(XP2972), S12(XP2020), S34(XP2020), (2 x 2 cm 2 ) used for active collimation; - signal amplification: differential readout based on NINO chip. - digital converters: CAEN TDC V1290N - DAQ – MBS (Multi-Branch System – GSI – Darmstadt) - information recorded for 2 central strips

16. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna 100 nA ≡ 975 Hz/cm 2 250 nA ≡ 1872 Hz/cm 2 Time resolution as a function of counting rate

17. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna 500 nA ≡ 3100 Hz/cm 2 Time resolution as a function of counting rate 750 nA ≡ 4430 Hz/cm 2

18. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Time resolution as a function of counting rate 1500 nA ≡ 8440 Hz/cm 2 3000 nA ≈ 16400 Hz/cm 2

19. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Time resolution as a function of counting rate No deterioration of the time resolution as a function of counting rate up to ~ 16 kHz/cm 2

20. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Conclusions and Outlook Three RPC prototypes based on PESTOV glass with a resistivity of ~10 10 Ωcm were tested in-beam in the first part of this year @ the ELBE facility at Forschungszentrum Dresden-Rossendorf. Standard readout Pestov glass RPC prototype. The 60 Co source tests show that the prototype has a good time resolution; Its performances in terms of time resolution -52 ps, were confirmed by the in- beam tests, fulfilling the requirement for the CBM-TOF subdetector. This time resolution was obtained in condition of a uniform exposure of the counter active area at a particle flux density of ~1kHz/cm 2. Differential strip readout RPC prototype was designed and built by us. The in-beam test showed the good performance of the counter with differential readout based on NINO chip in terms of time resolution – 69 ps. No significant deterioration of the time resolution as a function of counting rate was observed up to ~ 16 kHz/cm 2. Differential pad readout RPC prototype was also tested in-beam @ ELBE facility. The data are going to be analyzed.

21. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Participants NIPNE – Bucharest D. Bartos G. Caragheorgheopol M. Petris M. Petrovici V. Simion FZD – Dresden Rossendorf D. Stach F. Dohrmann R. Kotte L. Naumann J. Wüstenfeld GSI – Darmstadt K. Hildenbrand CERN - Geneva C. J. Williams

22. Mariana Petris, CBM Collaboration Meeting, October 13-18, 2008, Dubna Diferential pad readout RPC prototype Better granularity: Cell size: 0.5 x 2 cm 2